SWITCHING VOLTAGE REGULATOR WITH INPUT LOW VOLTAGE AND OUTPUT VOLTAGE DETECTORS

• US 3,754,182 A
• Filed: 10/02/1972
• Issued: 08/21/1973
• Est. Priority Date: 10/02/1972
• Status: Expired due to Term

• Current Assignee: Monroe Systems For Business, Inc. (Carolina Wholesale Office Machine Company, Inc.)
• Original Assignee: David Morris, Donald Conti
• Inventors: Morris, David, Conti, Donald
• Primary Examiner(s): Goldberg, Gerald
• Application Number:
  US05/294,277
• Time in Patent Office: 323 Days
• Field of Search: 323/4,9,17,22T,DIG.1 317/31,33R,33VR 307/297,290
• US Class Current: 323/299
• CPC Class Codes: H02H 3/243 for DC systems
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence

Abstract

A constant potential power supply having a Schmitt trigger regulator and switching amplifier to maintain the output load voltage within a predetermined range, and an undervoltage protection circuit which disables the regulator when the input potential goes below a predetermined level. An integrating capacitor which is part of the Schmitt trigger regulator, discharges through the load. The Schmitt trigger regulator is actuated when the output potential decreases below a certain maximum value and is disabled as the output potential goes below a certain minimum value; it is also actuated when the output potential increases to this minimum value and is disabled as the output potential goes below this maximum value. After actuation and until disabled, charging current is applied to the capacitor. The switching amplifier circuitry, which is coupled to the output load and the regulator, enables and disables the line switch of the regulator when the output voltage increases to this minimum value and when it decreases below this same minimum value. The output triggering section of the regulator disables the line switch when the output voltage increases above this maximum value and when it decreases below this same maximum value. The particular arrangement between the switching amplifier and the regulator provides significant control of the hysteresis as well as decreasing it and improving the overall regulation of the circuit.

Claims

1. An electrical power supply comprising:

first coupling means for coupling a direct current input voltage source;

Schmitt trigger amplifier means having an input terminal, an output terminal, and a first and second control terminal, said input terminal coupled to said first coupling means;

a switching amplifier means, having at least one control terminal and an output terminal coupled to said first control terminal of said Schmitt trigger amplifier;

output voltage detector means having an input terminal coupled to the output terminal of said Schmitt trigger amplifier, and an output terminal coupled to the second control terminal of said Schmitt trigger amplifier and said switching amplifier'"'"''"'"'s control terminal.

2. An electric power supply according to claim 1 additionally comprising:

an input voltage detector means having an input coupled to said first coupling means and whose output is coupled to said control terminal of said switching amplifier means.

3. An electric power supply according to claim 1 wherein said switching amplifier means comprises an electron valve means having a control electrode, and a first and second bias means coupled to said control electrode.

4. An electric power supply according to claim 3 wherein said electron valve means includes a transistor having a base electrode, and wherein each of said bias means includes a resistor, and wherein one end of each said resistor is coupled to said first coupling means and wherein the other end of one of said resistors is coupled to said base electrode.

5. An electric power supply according to claim 2 wherein:

said switching amplifier means includes a transistor having a base electrode and a first and second bias resistor, one end of said first bias resistor coupled to said base electrode and the other end coupled to one end of said second resistor to form a first junction; and

wherein said input voltage detector means comprises a voltage reference source coupled in series at said first junction with said second bias resistor.

6. An electric power supply according to claim 2 wherein said input voltage detector means causes said switching amplifier means to operate in its regulating mode when the input voltage at the first coupling means exceeds a first predetermined value.

7. An electric power supply according to claim 6 wherein said input voltage detector means further causes, in its undervoltage protection mode, said switching amplifier means to assume a first condition when the input source voltage at the first coupling means is below said first predetermined value.

8. An electric power supply according to claim 1 wherein said switching smplifier means, in its regulating mode, assumes a second condition when the output voltage at the output terminal goes above a second predetermined value, and assumes a first condition when the output voltage at the output terminal goes below said second predetermined value.

9. An electric power supply according to claim 8, wherein said Schmitt trigger amplifier means includes a first and second triggering means connected to said first and second control terminals respectively and a switching means coupled to the input terminal, and, in its Regulating mode, said second triggering means assumes a first condition when the output terminal goes above a third predetermined value and assumes a second condition when the output terminal goes below said third value, and wherein said switching means assumes a first condition when both said switching amplifier means and said second triggering means are in a second condition.

10. An electrical power supply comprising:

first coupling means for coupling a direct current input voltage source;

second coupling means for coupling a load;

Schmitt trigger regulator means having an input and output triggering stage, an input terminal, an output terminal, a series switching means coupled between said terminals, and a first and second control terminal, coupled to said load, said input terminal coupled to said first coupling means and said output terminal coupled to said second coupling means;

a switching means, having at least one control terminal one of which is coupled to said load and an output terminal coupled to said first control terminal of said Schmitt trigger regulator, for inhibiting said series switching means from conducting when said switching means is in a first state and enabling said series switching means to conduct when said output triggering stage is in a second state.